Overview of PWE3
Definition
Pseudo-Wire Emulation Edge to Edge (PWE3) is a point-to-point (P2P) technology that transmits Layer 2 services on a multiprotocol label switching Layer 2 virtual private network (MPLS L2VPN). PWE3 simulates essential attributes of a service such as Asynchronous Transfer Mode (ATM), Frame Relay (FR), Ethernet, low-speed Time Division Multiplexing (TDM) circuit, Synchronous Optical Network (SONET), and Synchronous Digital Hierarchy (SDH) on a Packet Switched Network (PSN).
Purpose
The IP network has developed rapidly in recent years because of its flexibility to upgrade, scalability, and interoperability. Conversely, the traditional communications network has low flexibility because it is limited by the transmission mode and services. To use existing or public network resources during upgrade and expansion of the traditional communications network, PWE3 can be used to integrate the traditional communications network and PSN.
PWE3 often applies to broadband metro access networks (MAN) or mobile bearer networks to transmit various services including Ethernet, ATM, TDM, FR, and PPP. As shown in Figure 1, the headquarters of company A and its branch are located on a traditional communications network such as ATM or FR. PWE3 is used to establish a PW between PE1 and PE2 so that the headquarters of company A and its branch can communicate over the MPLS network. PWE3 integrates original access modes with the existing IP backbone network to reduce repetitious network construction, saving operation costs.
PWE3 allows various services to be transmitted and supports migration from the mobile network to Long Term Evolution (LTE). PWE3 protects carrier investments when ATM and TDM services are migrated to the IP network.